Converting a stroke to a compound
path lets you modify the outline of the stroke. For example, you
can create a stroke with a varied width or divide the stroke into
pieces.
Select the object.
Choose Object > Path > Outline
Stroke.
The resulting compound path is grouped with the filled
object. To modify the compound path, first ungroup it from the fill
or select it with the Group Selection tool.
Use
the Layers panel to identify the contents of a group.